1. Field of the Invention
The present invention relates to a method for ion-exchanging and separating sodium and potassium, which is suitable for use, for example, as a method for selectively recovering potassium ions in sea water, whereby potassium can be efficiently recovered from sea water containing a large amount of sodium (0.6 mol).
2. Discussion of Background
Heretofore, separation among alkali metals has been successful in a case where lithium is separated by means of antimonic acid, or cesium is separated by means of titanic acid, by utilizing the difference in ionic radius. On the other hand, no satisfactory results have been obtained in the separation of adjacent sodium and potassium.
Therefore, as a method for recovering potassium from sea water containing a large amount of sodium (0.6 mol), it has been common to employ a method wherein chlorides of metals (including potassium) dissolved in sea water are all collected and then their separation is conducted by means of an organic ion exchange resin, etc. to recover potassium.
However, this method is not designed to directly and selectively recover potassium from sea water and has a problem that it is thereby difficult to obtain potassium in high purity.